Sales revenue for the period July-September 2013 reached £207 million - a 10% increase on the same period last year - and passenger numbers in summer 2013 rose 5% to 2.7 million.

The planned infrastructure investment has increase from £309 billion last year to more than £375 billion, with 291 of the 646 projects and programmes already under construction.

The decision by insurers Legal and General, Prudential, Aviva, Standard Life, Friends Life and Scottish Widows to invest in infrastructure follows changes in European rules pushed for by the UK which incentivise investment in a wider range of assets.

Mr Alexander will say: ''The announcement today that six major insurers will invest £25 billion over the next five years is a massive vote of confidence in the UK economy.

''It supports the wider £100 billion public investment to rebuild Britain over the next seven years that I announced at the Spending Round 2013. Underground, overground, onshore, offshore, wired or wireless, tarmac or train track. You name it, we're building it right now.

''This is great news for the people of the UK because after years of neglect, the UK's energy, road, rail, flood defence, communications and water infrastructure needs renewal.

''It will boost the UK economy creating jobs and making it easier to do business. It will also make the UK a better place to live for everyone who calls it their home.''

Association of British Insurers director general Otto Thoresen said: ''Insurers have a key role to play in contributing to the UK's economic growth, as providers of long-term capital investment. Providing capital for infrastructure projects will help drive a competitive, healthy and resilient UK economy.''

The decision to drop plans to toll the upgraded A14 has been welcomed by campaigners and follows David Cameron's acknowledgement of the ''strong feelings'' about the proposal in East Anglia.

RAC Foundation director Professor Stephen Glaister said: ''Piecemeal tolling that would raise little money but create a lot of aggravation and delay was always going to be a hard sell and not the best advert for pay-as-you-go driving.''

At Prime Minister's Questions last week, Mr Cameron said: ''I am well aware of the strong feelings in Suffolk about this issue and I have been approached about it by many Members of Parliament.

''I believe that road tolls can play an important part in providing new road capacity and it is important that we find ways to pay for road capacity, but I also understand the concerns about this individual case.''